AVIs are so freaking HUGE which is why I usually encode to a relitively high bitrate mpeg first. I need to maintain backups of my work for my clients so disk space is a major consideration.
As it is, I currently have over 60 Terabytes of backup drives. AVIs would push me to over 600TB and I can't afford that
And I manipulate the videos so heavily with filters, adjustments, and effects that it typically take 8 to 12 hours to render a single 20 or 30 minute scene so re-doing renders two or more times really isn't a viable option as Stan suggested.
When projects are 120 minutes or less, Encore does not typically have to re-Transcode. It is just on the rare occasion when a clients video runs over that length. I mean I *know* it is not ideal, but is the loss in image quality really that great to justify the additional time or cost of drvie space?